Centrifugal pump for a fuel tank



April 21, 1970 c. W.JEEP, JR., ETAL 3,507,582

CENTRIFUGAL PUMP FOR A FUEL TANK Filed Aug. 30, 1968 INVENTORS CHARLESW. JEEP, 3?.

ROONEY W. DAViS ATTORNEY United States Patent O 3,507,582 CENTRIFUGALPUMP FOR A FUEL TANK Charles W. Jeep, Jr., Webster Groves, and Rooney W.Davis, St. Louis, Mo., assignors to ACE Industries Incorporated, NewYork, N.Y., a corporation of New Jersey Filed Aug. 30, 1968, Ser. No.756,643 Int. Cl. F04d 9/.00

U.S. Cl. 417--366 7 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THEINVENTION The invention relates to a centrifugal fuel pump adapted to besubmerged in the fuel tank of an automobile. Important desiredcharacteristics of such fuel pumps are freedom from vapor lock,compactness, efficient cooling of the pump motor, simple structure andassembly, and unimpaired operation for an indefinitely long time withoutservicing. It is an object of the invention to meet these requirementsto a greater degree than that achieved by previous in-tank fuel pumps.Vapor lock is likely to occur in such pumps because the gasoline tank isheated by the air blown back from the engine and by the mufiler andexhaust pipes, reaching temperatures considerably above the ambienttemperature. Some vaporization of the fuel in the tank then takes place,especially since gasoline contains some light components which begin toboil below 100 Fahrenheit. As a result, a vapor bubble forms on the pumpimpeller and as the temperature rises the bubble becomes larger andlarger until a point is reached where the pump no longer pumps fuel.

SUMMARY OF THE INVENTION A fuel pump is provided for mounting at thebottom of an automobile gasoline tank. It includes a direct currentmotor having a vertical axis. The motor casing is formed of a metalliccylinder fitted with end closure members made of plastic material andconstituting the ends of a plastic pump housing. The end members providebearings for the motor shaft and passages for fuel and vapor, and theupper end member houses the motor brushes and has nipples for receivingwires connected to the brushes. A centrifugal impeller is connected tothe lower end of the shaft in a fuel receiving chamber in the bottom ofthe pump housing. The chamber provides clearance spaces around theimpeller for enabling vapor separated from the fuel to pass around theimpeller to its top side and then through an axial opening in the bottomof the housing. The housing has longitudinal internal ribs in which themotor casing fits tightly, and the ribs divide and seal the spacebetween the motor casing and the pump housing into separate fuel andvapor passages. The fuel and vapor flowing along the motor casing serveto cool the motor.

The various components of the motor structure are so arranged andconstructed that most of the major parts are simply placed one afteranother into the outer housing with no assembly operation other than theinsertion of the parts. Final assembly and sealing is confined to thetwo relatively simple steps of sealing two major end closure elements tothe outer housing after which an "ice outer cover and pump inlet cap ispressed into place at the lower end of the housing.

BRIEF DESCRIPTION OF THE DRAWING The invention is illustrated in theaccompanying drawing, whereinz FIGURE 1 is a top plan view of the pump.

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1.

FIGURE 3 is a partial section view along line 33 of FIGURE 1.

FIGURES 4 and 5 are half views of the top and the bottom of theimpeller.

FIGURE 6 is a selective section taken along line 66 of FIGURE 2.

FIGURE 7 is an enlarged partial sectional view of the bottom of thepump.

FIGURE 8 is a section taken along line 88 of FIG- URE 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT The fuel pump, which may rest onthe bottom of the fuel tank, as shown in Patents 3,090,318 and3,294,025, has an outer housing 10 formed of a plastic material having alow affinity for the contaminants which may be present. One suitableplastic material is acetal resin. Housing 10 includes a long cylindricalmember 12, a top member 14 and an inlet 16 at the bottom and a meshscreen or filter 18 for inlet 16. A rubber mount 20 may be fixed to thebottom of the fuel pump.

Within housing 10 is a direct current motor 22 having a commutator 24and a permanent magnet stator 26. The upper portion 28 of the motorshaft extends into a bore of top end member 14, which provides a bearingfor the shaft. Stator 26 is fixed in metallic cylinder 30, which isclosed by the center portion 32 of top member 14 and by bottom closuremember 34, which provides a bearing for portion 36 of the motor shaft.Member 34 at its upper end is snugly received by the inner surface ofthe lower end of casing 30. Member 34 is also provided with a supportingleg 34a and a supporting leg 3412. Since legs 34a and 34b are separate,they define an opening or openings 34c. Member 34 has a narrow slot 34extending across on a portion of its upper end which slot defines apassage 35.

Top member 14 houses a pair of motor brushes 37, 38, which engagecommutator 24, and a pair of conductors 39, 40 connected to the brushes.A nipple or outlet 42 for fuel and another outlet 44 for vapor areprovided, the latter outlet having a cap 46. Top 14 may be sealed tohousing 12 by a ring 48. Housing 12 is provided with three vertical ribs51, 52 and 53, which extend from partition 54 to top member 14. The ribsare longitudinally serrated to form liquid and vapor tight seals againstmotor casing 30, which the ribs hold centered and spaced from housing12. The spaces between housing 12 and casing 30 form separate channelsor passages 56, 57, 58 for fuel and vapor. Top member 14 has channels 60and 62 connecting passages 56 and 58 tooutlets 42 and 44.

At the bottom of casing 10 is a perforated plate 71 through which fuelfrom inlet 16 passes into pump chamber 66. Impeller has a hub 64 mountedon the end of shaft 36. The bottom side of impeller 70 has arcuate vanes72 on a plate 74, and the top side has a ridge 76 and short peripheralvanes 78 outside ridge 76. Chamber 66 has a volute portion 80 and avolute outlet 82 through which the fuel flows upwardly into passage 56and 60 to fuel outlet 42. Chamber 66 provides an adequate clearancespace around impeller 70 for the movement of vapor. The centrifugalaction of the impeller on the liquid fuel propels the fuel throughvolute 80 and outlet 82, but the vapor is forced by fluid pressure torise to the top side of the impeller or chamber 66 and move into the lowpressure area at the top center portion 84 of the impeller. The vaporthen moves or bubbles out through opening 86 of partition 54, and thenthrough space 340 of closure member 34. The vapor then rises throughpassages 57 and 58, channel 62 and outlet 44.

The operation of the fuel pump generally will be apparent from theforegoing description. The pump will be fixedly mounted on the bottom ofa fuel tank by any suitable means. Fuel enters through filter 18 andpasses through perforated plate 71 into pumping chamber 66. Vanes 72 onthe bottom side of the impeller cause the liquid fuel to circulate andmove outwardly and pass into volute section 80 and opening 82 and thenupwardly through passage 56 to outlet 42, which of course is connectedby a fuel line to the carburetor. In passing through passage 56, thefuel bathes a substantial portion of metallic casing 30 of the motor,and thus serves to cool the motor. A portion of the fuel (now underpressure) in channel 56 passes through the passage 35 in member 34 torise upwardly through the interior of the motor to supply additionalcooling thereto. This portion of the upwardly rising fuel passes out ofthe motor enclosure by way of clearance in the bearing surroundingportion 28 of the motor shaft, thence upwardly through restriction 15and out through the top member 14. Vapor in the fuel moves through theclearance space around impeller 70 and rises to the top side thereof.Liquid fuel tending to flow around to the top side of the impeller isreturned by the short peripheral vanes 78 on the top side, and ridge 76acts as a barrier to flow of liquid over the top side of the impeller.The vapor, however, moves along the top of chamber 66 and passes overbarrier 76 of the impeller and then out through openings 86 and 88,passages 57 and 58, and is returned to the fuel tank through outlet 44.In passages 57 and 58 the vapor moves along motor casing 30 and helps tocool it.

It is to be mentioned that leg 34a of member 34 has sufiicient length tobridge across the space between ribs 51 and 52 thereby enclosing so muchof passage 56 as is defined by member 34. Casing 30 defines theremainder of passage 56.

Assembly of the motor-pump is easy and simple. The rotor is slippedinside the stator 26 which already includes the casing 30. Bottom member34 is slipped onto the lower end of the rotor shaft and top member 14 isslipped onto the other end. The foregoing sub-assembly is then forcedinto the housing 12 until the member 34 comes to rest on the partition54. Forcing the casing 30 into the housing 12 is necessary because thereis an interference fit with the ribs 51, 52 and 53' which forms the sealreferred to earlier. Subsequent assembly operation includes installationof the impeller 70, and the perforated plate 71. Plate 64 is secured inplace by rolling the edge of the housing over the plate, as by applyingheat. The inlet cap is then pressed into position. If a press fit isused, the inlet cap need not be otherwise secured. A final assemblyoperation is the installation of securing ring 48 which can be heatsealed or glued in place. This completes the major portion of theassembly operation. The electrical lead wires and brushes can beinstalled at any suitable time in the operation.

We claim:

1. An electric fuel pump for use in a liquid fuel tank comprising:

(a) an electric motor adapted to be mounted vertically and having ashaft extending downwardly therefrom,

(b) a centrifugal impeller mounted on the shaft,

(0) an elongated cylindrical housing of plastic material enclosing saidmotor and impeller, said impeller including a circular plate having aplurality of outwardly extending vanes on the bottom of said plate,

(d) means for obstructing radial flow of liquid fuel along the top ofsaid plate,

(e) said housing having a fuel inlet passage extending to the bottom ofsaid impeller and a fuel outlet adjacent the periphery of the impeller,said housing also providing a passage for vapor round the impeller fromthe bottom portion thereof to a central portion of the top of theimpeller, and

(f) an outlet passage extending upwardly through the housing from thecentral portion of the top of the impeller for emitting vapor separatedfrom the fuel by the impeller.

2. A pump according to claim 1, wherein said housing has a plurality ofinternal, vertically extending ribs, a cylindrical metallic casingsurrounding said motor located within said housing and tightly engagingsaid ribs, the space defined by the portions of the walls of the housinand casing between two said ribs forming a passage communicating withsaid outlet passage for the vapor, and another space defined by otherportions of the walls of said housing and casing forming a fuel passagecommunicating with said fuel outlet.

3. A pump according to claim 2, wherein said casing for the motorextends along a major portion of the passages defined =by said ribs,whereby the vapor and fuel flowing through the passages cool the motor.

4. An electric pump according to claim 3, comprising a member forclosing the bottom of said casing for the motor, said member having aclose-fitting bearing for the motor shaft, said member having apartition extending between two of said ribs for separating the fuelpassage between these ribs from the passage for the vapor.

5. An electric pump according to claim 4, comprising a plastic topmember adapted to fit on the top of said housing and having a lowerportion engaging and closing said casing for the motor, said top memberhaving a pair of vertical openings for a pair of motor brushes, said topmember having also a bore for an upper portion of the motor shaft andseparate outlets for vapor and fuel.

6. An electric pump according to claim 1, wherein said means forobstructing radial flow of liquid fuel along the top of the impellerplate includes a closed annular ridge on the top of said plate.

7. An electric pump according to claim 6, including a plurality of vaneson the top of said plate extending from said annular ridge to theperiphery of said plate.

References Cited UNITED STATES PATENTS ROBERT M. WALKER, PrimaryExaminer US. Cl. X.R. 417-424

